In the design of water supply, drainage, and fire protection systems for petrochemical industries, how should the outer diameter and wall thickness of steel pipes be determined?
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In the design of water supply, drainage, and fire protection systems for petrochemical industries, how should the outer diameter and wall thickness of steel pipes be determined? For example, for DN200 seamless steel pipes, I use D219x6, but how should I choose the wall thickness? Previously, we followed the ASME standard and used Sch40; in that case, it wasn’t 6 inches thick. But what exactly is Sch40? Why choose Sch40 instead of Sch60 or Sch80?
SCH in steel pipes, pipe fittings, and flanges is an abbreviation for Schedule; it refers to the wall thickness designation for pipes and pipe fittings according to American standards. SCH5, SCH10, SCH20, SCH40, SCH80, and so on represent different wall thicknesses.
You’re right, but what I want to ask is why that SCH 40 was chosen. As for how to choose exactly which wall thickness to use, in theory, there is no need to calculate the wall thickness for pipes used for drainage
In my opinion, the wall thickness is related to the surrounding environment and the pressure inside the pipeline; if anti-corrosion measures are properly implemented, the design pressure of the pipeline can meet the requirements for use, so the choice can be made based on the specific circumstances of the enterprise. There are no requirements regarding wall thickness. But the higher the design pressure of your pipeline, the thicker the wall thickness must be, right (under the same material and type conditions).
The wall thickness of all pipes needs to be calculated; however, since drainage pipes are used under fewer operating conditions, one wall thickness grade is sufficient. In contrast, process pipes require that their wall thicknesses be determined under various conditions. As for why Sch40 is used, it’s the result of calculations; those who are interested can delve into it further, while those who aren’t should follow the regulations